Is Buying a Prius Really Good for the Planet?

In his book, The Conundrum, New Yorker staff writer David Owen ruffles the feathers of energy-efficiency advocates with his argument that living sustainably often means living, in his words, “pretty much the way I live right now, though maybe with a different car.” He argues that no matter how many Priuses, LED bulbs, and vegetarian entrees we buy, we won’t save the planet, because we’ll negate the energy (and money) savings by spending them on some other energy-sucking activity.

Owen’s argument rings true to anyone who’s rationalized leaving the extra-efficient lights on when rushing out of the house (guilty) or eating a hamburger after a few meat-free meals (guilty again). But there’s plenty of evidence that consumption justified by sustainable choices doesn’t eat up all the energy saved. A new bit of research makes that case for the Prius, a quintessential green purchase.

CO2 Scorecard, a nonprofit research group, enlisted Yale professor Ken Gillingham to help compare the driving habits of Prius owners and everyone else. The researchers found Prius owners in California drove only a tiny bit more—an average of 0.5 percent—than other drivers, despite their lower gas bills.

That makes sense for a few reasons. First, plenty of people buy fuel-efficient cars like the Prius to save money, not to save the environment. Both my parents own hybrid vehicles, but they don't go for joyrides under the theory they've saved so much gas that they've got some to burn. They drive the same way they always did, enjoying the cheaper gas bills and the knowledge that they’re not using as much gas as they would be otherwise.

Using the same amount of gas as they did before they owned a Prius would required spending a lot more time in the car. As Matthew Kahn, an economic professor at UCLA, wrote in TheChristian Science Monitor last month, “Behavioral responses to price declines are not that large. The reason for this is that we often need to use our own time when we use a product that consumes electricity.” My parents would have to change their behavior dramatically— to go on long road trips every weekend, for instance—to reinvest all of the money they've saved, but they don't have time to do that.

So California Prius owners might not have increased their driving, but what if they spent that extra gas money on plane tickets, gigantic steak dinners, or other similarly environmentally unfriendly expenditures? There’s some disagreement among energy-efficiency experts about how large these rebound effects can be. But only a handful think that all the energy saved is sunk back into other energy-intensive pursuits. The case isn’t so clear for, say, backyard chickens, another green “fad” Owen takes issue with, but it's safe to say Prius owners are doing their part to improve the planet.